Universal power-law distribution functions in an electromagnetic kinetic plasma: implications for the inverted temperature profile in the solar corona

TL;DR

This paper presents a self-consistent theory showing that electromagnetic turbulence in plasmas leads to universal power-law tails in particle distributions, explaining the inverted temperature profile observed in the solar corona.

Contribution

It introduces a novel quasilinear framework demonstrating universal $v^{-5}$ tails in plasma particle distributions, with implications for solar corona phenomena.

Findings

Electromagnetic turbulence induces universal power-law tails in plasma distributions.

The non-thermal tail facilitates suprathermal particle escape from the sun.

Inversion of the temperature profile in the solar corona is explained by this mechanism.

Abstract

We develop a self-consistent quasilinear theory for the relaxation of electromagnetic kinetic plasmas, and demonstrate that the mean distribution functions of both electrons and ions tend to relax to a universal $v^{-5}$ tail. Large-scale electromagnetic (EM) fields efficiently accelerate the unscreened, fast particles but not the screened, slow ones. This non-thermal tail may arise in the solar corona from EM turbulence despite collisions, allowing suprathermal particles to escape the sun's gravity (velocity filtration) and inverting the temperature $(T)$ profile with $T$ rising to $10^6$ K.